Clamping support for grinding machines



B. BETHKE.

CLAMPING SUPPORT FOR GRINDING MACHINES. APPLICATION HLED MAR.'I0. 1920.

1,404,337, Patented Jan. 24, 1922.

IBERNHABD BETHKE, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO LUTHER G BIND RMFG. 00., 0F MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

CLAMPING SUPPORT FORGRINDING MACHINES.

Specification of Letters Patent.

Patented Jan. 24, 1922.

Application filed March 10, 1920. Serial :No. 364,715.

To all whom it may concern:

Be it known that I, BERNHARD BETHKE, a citizen of the United States,residing at Milwaukee, county of lvlilwaukee, and State of Wisconsin,have invented new and useful Improvements in Clamping Supports forGrinding Machines, of which the following is a specification. Myinvention relates to improvements in clamping supports for grindingmachines and other small manually driven tools adapted to be secured toa bench or table. The object of my invention is to provide means wherebya grinding wheel or other rotative tool may be supported to revolyeabout an axis oblique to the front margin of the bench or table, anddriven by a crank which revolves in a plane oblique to such margin, themachine being adequately secured and rigidly held to such bench ortable, notwithstanding its oblique position. It is a further object ofmy invention to provide means whereby grinding wheel mechanisms andsimilar devices may be not only supported in the oblique position abovementioned, but may also, with equal facility,

be clamped to the table or bench in the ordi-.,

nary manner, with the tool supporting arbor or shaft at right angles tothe front margin of the support.

In the drawings Figure l is a plan view of agrinding wheel clampingsupport embodying my invention, showing the same as it appears in usewith the grinding wheel arbor obliquely disposed.

Figure 2 is an elevation of the mechanism, including the clampingsupport.

Figure 3 is a sectional view, drawn to a plane on line 8 of Figure 2.

Like parts are identified by the same reference characters throughoutthe several views.

The grinding wheel casing 1 may be of any ordinary type. The casingillustrated is provided with a driving shaft 2 having an exterior crank23. The driven shaft or arbor 4- supports the grinding wheel 5, and isdriven from the shaft 2 by a gear wheel and pinion, indicated by dottedlines at 6 and 7. All of these parts, however, may be of any ordinaryconstruction.

But it will he observed that the casing 1 is supported by a base plate10, preferably formed integrally with the bottom and front wall of thecasing, but this base plate 10 is of peculiar contour. It is of agenerally triangular form, with the right hand side margin 10 extendingforwardly to an apex 10 located at the'right of'a vertical plane throughthe axis of the crank shaft 2. The left hand margin has one portion 10extending from the left hand side of the casing toward the verticalplane of the crank shaft, along a line which is substantially parallelto the margin lQ-of the table or bench when the device is secured tosuch table with the arbor 4, at an angleof approximately 45 to the tablemargin. Between the portion 10 of the base plate margin and the apex10', the base plate margin is outwardly curved, as indicated at 10 andthis outwardly extending portion of the plate is provided with adepending arm 13 having a horizontally extending extremity 141, whichprojects underneath the table or bench, and through which a clamping setscrew 15 passes, the upper end of this set screw being provided with aswiveled clamping head 17 adapted to engage the under surface of thetable or bench, whereby the set screw may be utilized to draw theclamping plate 10 forcibly downwardly on the upper surface.

It will be observed that the form of the clamping plate 10 is such thatthe right hand marginal portion 10 extends inwardly upon the surface ofthe table along a line substantially at right angles to the margin 12 ofthe table, although the base plate margin is preferably slightly curvedfor the purpose of attractive design. 'lherefore. space is provided at16 for the crank handle, the same being allowed to turn without strikingeither the base plate or the table.

On the other side,(i. e.,the left hand side), the contour of the baseplate 10 is such as to interfere to a minimum extent with themanipulation of tools and devices of various kinds which are beingsubjected to a grinding operation. The fact that the grinding wheelrevolves in an oblique plane is of great importance for the reason thatmany tools, such as chisels and long knives, or other tools with longhandle, are frequently of such character that in order to get the bestresults the handles must be swung down wardly across the plane of thetable, and un less the grinding wheel is located in an oblique planesuflicient clearance cannot be obtained.

Where ordinary clamping plates are employed, the desired adjustment ofthe grinding wheel cannot be secured,-at least with out greatlyweakening the clamping engagement with the table. This is true for thereason that when the casing is rotated to the oblique position, theclamping arm corresponding with the arm 13 will strike the table on theright hand side,whereas the upper clamping plate will be entirely out ofcontact with the table on the left hand side, and the clamping pressurebeing exerted considerablyto the right of the center of gravity of themachine, considerable vibration results in operation, and the fasteningbecomes very insecure.

By my improvement, the clamping arm '13 is brought to the left, and theclamping pressure is exerted centrally, i. e., substantially directlybelow the center of gravity of the machine. The wide bearing area of theclamping plate upon the table at the points most distant from its frontmargin 12 and from the point at which the arm v13 is located, is also afactor in securing rigidity and stability for the support.

The larger area of the clamping plate is provided at the right hand forthe reason that the majority of users operate the grinding machine withthe right hand, and hold the tool with the left hand. Therefore, thedescribed contour of the clamping plate provides clearance for the toolat the side where clearance is normally desired.

I claim A. clamping support for grinding machines and similar tools,comprising a base plate of substantially triangular contour, a gearcasing carried by said base plate adjacent one of the triangular sides,said gear casing having a driving shaft bearing arranged at an acuteangle to another of said triangular sides, and a clamping armextendingdownwardly from said last mentioned side and beneath said base plate.

In testimony whereof I afiix my signature in the presence of twowitnesses.

BERNHARD BETHKE.

Witnesses v 7 LEVERETT C. WHEELER, 0. O. WEBER.

